Glycobiology of syndecan-1 in bacterial infections.

Syndecan-1 (Sdc1) is a major cell surface heparan sulfate (HS) proteoglycan of epithelial cells, a cell type targeted by many bacterial pathogens early in their pathogenesis. Loss of Sdc1 in mice is a gain-of-function mutation that significantly decreases the susceptibility to several bacterial infections, suggesting that subversion of Sdc1 is an important virulence strategy. HS glycosaminoglycan (GAG) chains of cell surface Sdc1 promote bacterial pathogenesis by facilitating the attachment of bacteria to host cells. Engagement of cell surface Sdc1 HS chains by bacterial adhesins transmits signal through the highly conserved Sdc1 cytoplasmic domain, which can lead to uptake of intracellular bacterial pathogens. On the other hand, several bacteria that do not require Sdc1 for their attachment and invasion stimulate Sdc1 shedding and exploit the capacity of Sdc1 ectodomain HS GAGs to disarm innate defense mechanisms to evade immune clearance. Recent data suggest that select HS sulfate motifs, and not the overall charge of HS, are important in the inhibition of innate immune mechanisms. Here, we discuss several examples of Sdc1 subversion in bacterial infections.

Molecular functions of syndecan-1 in disease.

Syndecan-1 is a cell surface heparan sulfate proteoglycan that binds to many mediators of disease pathogenesis. Through these molecular interactions, syndecan-1 can modulate leukocyte recruitment, cancer cell proliferation and invasion, angiogenesis, microbial attachment and entry, host defense mechanisms, and matrix remodeling. The significance of syndecan-1 interactions in disease is underscored by the striking pathological phenotypes seen in the syndecan-1 null mice when they are challenged with disease-instigating agents or conditions. This review discusses the key molecular functions of syndecan-1 in modulating the onset, progression, and resolution of inflammatory diseases, cancer, and infection.

Mutations in the epidermal growth factor receptor (EGFR) gene in triple negative breast cancer: possible implications for targeted therapy.

INTRODUCTION: Triple negative breast cancer is associated with poorer prognosis and unresponsiveness to endocrine and anti-HER2 directed agents. Despite emerging data supporting the use of polyADP-ribose polymerase (PARP) inhibitors, complete and durable responses are rare and exploration of additional targeted therapies is needed. Epidermal growth factor receptor (EGFR) is expressed in triple negative breast cancer and several clinical trials are testing the role of anti-EGFR directed therapy. However, the rate of EGFR mutations is poorly defined. We, therefore, sought to characterize EGFR mutations in triple negative breast cancers. METHODS: Seventy samples were randomly chosen from a cohort of 653 triple negative breast tumours for EGFR mutation analysis. These samples were immunostained for EGFR protein expression and consisted of negatively stained and positively stained cases. DNA was extracted from paraffin blocks and polymerase chain reaction was performed to amplify exon regions 18 to 21 of the EGFR gene. Direct sequencing of the purified PCR products was performed. RESULTS: EGFR mutations were found in 8 of 70 samples (11.4%). Mutations were predominantly exon 19 deletions (4 of 70 samples, 5.7%), which clustered in the region spanning codons 746 to 759 within the kinase domain of EGFR. Two types of exon 19 deletions were seen: a 15 nucleotide deletion (del E746-A750) (2 of 70 samples) and a 24 nucleotide deletion (del S752 - I759) (2 of 70 samples). Other exon 19 mutations observed were the inversion of the complementary strand (1 of 70 samples). Exon 21 mutations included missense substitution, L858R (1 of 70 samples) and T847I (2 of 70 samples). Mutations observed were independent of EGFR protein expression determined by immunohistochemical staining. CONCLUSIONS: This study is among the first to document the presence and estimate the prevalence of EGFR mutations in triple negative breast cancer. These findings have potential implications for the design of clinical trials involving anti-EGFR directed therapy which currently do not select for patients based on presence of activating EGFR mutations, which may hence be underpowered to detect significant benefit in unselected populations. More complete sampling of EGFR mutation status in triple negative breast cancer is needed to determine the true mutation rate.

Glomerular basement membrane thickness in an Asian population using a novel image analysis software.

AIMS: We aimed to develop an image analysis software that enabled measurement of glomerular basement membrane (GBM) thickness. METHODS: With this software, we evaluated the range of GBM widths found in a cohort of Asian patients diagnosed with a spectrum of renal diseases including minimal change/IgM nephropathy, focal and segmental glomerulosclerosis, IgA nephropathy, systemic lupus erythematosus nephritis, diabetic nephropathy, pauci-immune crescentic glomerulonephritis, thin basement membrane disease, and tubulointerstitial nephritis. Measurements were taken from a minimum of five glomerular capillary loops of each glomerulus. For each loop, at least 10 different points of the GBM were measured. RESULTS: The average GBM width measured for minimal change disease was 347.4 +/- 9.0 nm, with the highest value being 403.9 nm and lowest being 214.7 nm. No association was found between GBM width and gender. We found a significant increase in GBM width in pathological states like lupus nephropathy (p < 0.0001), diabetic nephritis (p < 0.001) and tubulointerstitial nephritis (p < 0.01) as compared with minimal change disease. Only one case of thin membrane nephropathy (198.7 nm) was available for analysis and we found a significant thinning of the GBM. CONCLUSIONS: These observations provide insights into the range of GBM thickness in several disease states and support the use of this novel software in the daily diagnostic laboratory setting.

Increased expression of non-sulfated chondroitin correlates with adverse clinicopathological parameters in prostate cancer.

Chondroitin sulfate is a structurally diverse glycosaminoglycan, which contains a variable degree of sulfation that helps to determine its biological function. It is involved in the regulation of cellular activity and has been implicated in carcinogenesis. To determine if the non-sulfated chondroitin backbone has a functional role in prostate cancer, we analyzed its expression by immunohistochemistry using the 1B5 monoclonal antibody and a set of tissue microarrays constructed with 227 prostate specimen cores from 81 cases of benign prostate tissue and 77 cases of prostate cancer, of which 69 of these cases are matched. Non-sulfated chondroitin was found in the secretory epithelial cells and stromal regions of both prostatic adenocarcinoma and benign prostatic tissues, as well as in the basal cells of benign glands. A higher percentage of cancerous cells were stained positively for non-sulfated chondroitin as compared with benign secretory cells of the same patient. Cancerous cells stained more intensely for non-sulfated chondroitin. This increase in percentage of cells stained and increase in staining intensity were associated with higher pathological T stage and extraprostatic extension. Non-sulfated chondroitin expression (either staining intensity or percentage of cells stained) in adenocarcinoma and its peritumoral stroma correlated significantly with several clinicopathological parameters of unfavorable outcome, including higher pathological T stage and Gleason score, presence of tumor in both prostatic lobes, extraprostatic extension, seminal vesicle involvement and preoperative prostate-specific antigen levels. These data suggest that non-sulfated chondroitin is a potentially useful biomarker for prostate cancer, and may be involved in regulating prostate cancer behavior.